60V, 4A regulator; adjustable output & wire-drop compensation

January 19, 2016 // By Graham Prophet
LTC3649 is a high efficiency, 60V, 4A synchronous buck regulator that incorporates a constant frequency, current mode architecture and programmable output current and output voltage; it operates from an input voltage range of 3.1V to 60V and provides an adjustable rail-to-rail output voltage range from 0V to 0.5V below VIN, while delivering up to 4A of continuous output current.

Its wide input and output voltage range is suitable for test, measurement and industrial applications. LTC3649’s design includes an accurate internally generated 50 µA current source on the ISET pin, enabling it to deliver outputs as low as 0V with the use of a single external programming resistor. It offers ±0.8% output voltage accuracy and programmable output current with ±4% accuracy without a sense resistor. Its switching frequency is user-programmable from 300 kHz to 3 MHz, enabling the use of tiny, low cost capacitors and inductors. Combined with a 28-lead 4 x 5 mm QFN or thermally enhanced TSSOP package, the LTC3649 offers a compact solution footprint.

The regulator uses internal power switches with R DS(ON) of 100 mOhms and 50 mOhms to deliver efficiencies as high as 95%. Burst Mode operation offers high efficiency at light loads, requiring only 440 µA of quiescent current. For noise sensitive applications, the LTC3649 can run in forced continuous mode, offering very low output ripple. Additional features include ±4% accurate output current monitoring, a power-good voltage monitor, programmable wire drop compensation, external synchronization capability and thermal protection.

The LTC3649EUFD is available in a 4 x 5 mm QFN-28, the LTC3649EFE is offered in a 28-lead, thermally enhanced TSSOP package. Industrial grade versions, the LTC3649IUFD and LTC3649IFE, are guaranteed to operate over the -40°C to 125°C operating junction temperature range. Pricing starts at $5.65 (1,000).

Linear Technology; www.linear.com/product/LTC3649